The progress in development of the Planck-Balance 2 (PB2): A tabletop Kibble balance for the mass calibration of E2 class weights

Abstract

In this paper we present the progress in development of a table-top version of the Kibble balance under the name Planck-Balance 2 (PB2). The PB2 is developed as a collaboration effort between the Technische Universität Ilmenau (TU Ilmenau) and Physikalisch-Technische Bundesanstalt (PTB) aiming for automatized mass calibration of the set of weights in the range from 1 mg to 100 g within the required uncertainties as stated by OIML recommendation R111 for weights of E2 class. We describe the design and the operational performance of the PB2 system in detail, the results of rigorous investigations of the error sources and subsequent improvements made since the beginning of the project in early 2017, the measurement data with the corresponding relative uncertainties and the preliminarily obtained uncertainty budget.

Deploying the high-power pulsed lasers in precision force metrology -- SI traceable and practical force quantization by photon momentum

“…This allows measuring mass artifacts in the 1 mg to 100 g range in the laboratory without access to any calibrated masses, instead with direct traceability to the Planck constant by quantum electrical measurements. Note that the calibrations are typically performed for a specific set of nominal masses values, however, with the PB2 system [7] we demonstrated also by 'quasi-blind' measurement campaign using a set of uncalibrated mass pieces that it is capable of mass calibrations for other mass values along the continuous scale. Additionally, it is delivering the necessary level of measurement uncertainty required by universally accepted guidelines OIML R 111-1 [22].…”

“…Under the construct of the differential signal, by combining the operation of both EMFC balances together, a reduction of common-mode noise due to tilt or accelerations or temperature changes is obtained. They perform a common force calibration measurements routine based on Kibble balance principle [7], [14] supported by the necessary opto-electrical measurement infrastructure to enable the SI traceability of the main measurement quantities. The low stiffness of the flexurebased parallel-beam guiding mechanism, the high lever ratio of force transmission, and the extensively well-characterized coil and closed-circuit magnet system assembly nested inside the EMFC balances provide extremely high force sensitivity and reproducibility.…”

“…Owing the progress achieved in recent years in developments of tabletop versions of the KBs, e.g. Planck-Balance 2 (PB2) [7], [20] or KIBB-g1 [21], the realization of the optical power (or small calibration force) measurements can be undertaken with similar systems, where the requirements on the level of the uncertainties attached to each measurement quantity are relaxed in comparison with KB systems. As an example, with the PB2 apparatus, typical measurement uncertainties required for industrial mass calibration in accordance to OIML R 111-1 for weights of E2 class [22] is achieved.…”

“…The basis for the development of an SI-traceable framework for the measurements of mass, force, and the optical power of the lasers via photon momentum-based force generation and quantum electrical measurement is a special measurement routine that uses the KB principle [14]. This principle, in recent decades promoted for determination of Planck's constant and further adapted for determining the mass and dissemination of the quantum-based kilogram, has been extensively studied since the first reports in the late 1970s [7]. The KB (formerly known as Watt balance) relies on precise virtual comparison of mechanical and electrical powers obtained from two-step experiments both based on electromagnetic interaction and with the use of macroscopic quantum effects, the Josephson and the quantum Hall effect.…”

“…T HE redefinition of the International System of Units (SI) stimulated a new quest for developing ever improved methods supporting the calibration tasks in the fields of precision mass/force metrology and 'unsurprisingly' in high power optical (laser energy) metrology [1]- [6]. Specifically, as of the recent advances in macroscopic realization of the quantum-based kilogram, defined by a natural constant and emerged from quantum mechanics -namely the Planck constant which in itself is already numerically exactly defined as h=6.626 070 15•10 −34 J Hz −1 , -guiding methods arose for improving the accuracy of quantification of the optical power of high energy lasers covering the range from 1 W to 10 5 W and above, and for generation of reference calibration small forces ranging from 10 −5 N to 10 −8 N and below [7]- [10]. One of the methods reintroduced in the last decade is the quantum-based realization of small forces using the effect of the momentum transfer of the absorbed and re-emitted photons from the ultra-high reflective mirrors -the radiation pressure [11].…”